561 results about "Ferric" patented technology

The invention relates to the technical field of water treatment, and discloses a modified polyaluminum chloride flocculant and a preparation method thereof.The modified polyaluminum chloride flocculant is prepared from, by weight, 50-65 parts of polyaluminum chloride, 8-12 parts of magnesium silicate, 5-8 parts of carboxymethyl chitosan, 15-25 parts of polyaluminum ferric chloride and 3-5 parts of tea polyphenol; the molar ratio of aluminum ions to iron ions in the modified polyaluminum chloride flocculant is (3-4.5): 1. According to the invention, an inorganic-organic dual-modifier synergistic effect mechanism is adopted to construct a'rigid framework-flexible network 'composite structure, and the structure can significantly improve the adsorption capacity of Pb < 2 + >. Meanwhile, the mechanical property of the flocculating agent is improved, so that the flocculating agent can be applied to a high-turbulence environment.

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a sodium ferric pyrophosphate positive electrode material as well as a preparation method and application thereof. The invention provides a preparation method of a sodium ferric pyrophosphate positive electrode material, which comprises the following steps: (1) mixing an iron source, a sodium source, a phosphorus source and citric acid for the first time, and performing spray drying for the first time to prepare a first precursor with D50 of 10-12 [mu] m; performing secondary mixing on an iron source, a sodium source, a phosphorus source and citric acid, and performing secondary spray drying to prepare a second precursor with D50 of 3-5 microns; the iron source comprises a first iron source with D50 of 1.1-1.8 [mu] m and a second iron source with D50 of 0.3-0.8 [mu] m; the mass ratio of the first iron source to the second iron source is (0.3-0.5): (0.5-0.7); and (2) mixing the first precursor, the second precursor and sodium metaborate, and sintering to obtain the sodium ferric pyrophosphate positive electrode material. After the prepared pyrophosphate ferric phosphate sodium positive electrode material is prepared into a pole piece, the compaction density is proper, and the prepared battery is high in specific capacity and cycle performance.

The invention discloses a composite water purifying agent based on polyaluminum ferric sulfate. The preparation process comprises the following steps: 1, reacting ferrous sulfate heptahydrate, aluminum sulfate, sodium chlorate, phosphoric acid and the like to prepare a polyaluminum ferric sulfate solution; 2, mixing the modified polyacrylamide solution with the polyaluminum ferric sulfate solution for reaction to obtain a composite system; and step 3, adding acidic ochre soil into the composite system to obtain the composite water purifying agent. The preparation method has the beneficial effects that a modified monomer is prepared through organic synthesis, and the modified monomer is copolymerized with monomers such as acrylamide to prepare modified polyacrylamide; then, the organic polymer is compounded with a polyaluminum ferric sulfate solution and acidic ochre soil, and an inorganic-organic-mineral ternary water purification system is constructed; the composite water purifying agent has the high-efficiency electricity neutralization capability of an inorganic flocculating agent, the bridging flocculation effect of organic macromolecules and the adsorption performance of minerals, and shows excellent flocculation and sedimentation effects and pollutant removal capability.

The invention provides a purification and impurity removal method of a crude nickel-cobalt-manganese sulfate solution. The purification and impurity removal method comprises the following steps: (1) adding sodium thiosulfate into the crude nickel-cobalt-manganese sulfate solution to remove copper; (2) phosphate is adopted, the pH value is regulated, and titanium, iron, aluminum and the like are removed; (3) ferric sulfate is added, the pH value is regulated, and phosphorus and silicon are removed; (4) adding a bismuth agent and regulating the pH value to remove chlorine; (5) adding a fluorine agent to remove calcium and magnesium; and (6) adding a tillite mineral adsorbent to remove fluorine. According to the method, iron, aluminum, copper, fluorine, phosphorus, titanium, calcium, magnesium, chlorine, silicon and other elements can be efficiently removed from the rough nickel-cobalt-manganese sulfate solution, the loss of main metal is low, the prepared high-purity nickel-cobalt-manganese sulfate solution can directly meet the requirement of a precursor solution of a battery preparation level, the process is simple, the operation difficulty is low, industrial large-scale production is easy to achieve, and the method is suitable for industrial production. And the defects of the current preparation method of the high-purity nickel-cobalt-manganese sulfate solution are overcome.

The invention discloses ferric sodium pyrophosphate, a preparation method, a positive pole piece and a sodium ion battery, and belongs to the technical field of secondary batteries. The preparation method comprises the following steps: S1, mixing a phosphorus element, an iron element, a sodium element and a carbon element in a phosphorus source, an iron source, a sodium source and a carbon source according to a molar ratio of (1-5): (1-3): (1-5): (0.1-0.5); adding a dispersing agent and an organic solvent; s2, carrying out ball milling on the mixture obtained in the step S1; s3, carrying out vacuum drying on the mixture subjected to ball milling; and S4, sintering the material treated in the step S3 to obtain the ferric sodium pyrophosphate. The preparation method of the ferric sodium pyrophosphate comprises the following steps: uniformly mixing a phosphorus source, an iron source, a sodium source and a carbon source through ball milling, and sintering to obtain the ferric sodium pyrophosphate. The ferric sodium pyrophosphate is prepared by adopting a solid phase method, the preparation steps are simple, and large-scale production is easier.

The invention relates to a special fertilizer suitable for saline-alkali soil and a preparation method thereof. The fertilizer is granular and has a multi-layer structure which is sequentially arranged from inside to outside: a nutrition core layer, a controlled release film layer, a soil improvement fast exchange layer and a microorganism attaching layer. The nutrition core layer contains nitrogen, phosphorus, potassium and medium trace elements, and meets the basic nutrient requirements of crops; the controlled release film layer is self-assembled layer by layer by adopting alginate / chitosan, a humic acid-ferrous complex and a breakable cross-linking point are inserted into the film, and starch is sprayed on the outer layer, so that an ionic strength / alkalinity dual-response controlled release system is formed; the soil improvement quick exchange layer contains microcrystalline gypsum and ferrous sulfate; the microbial epiphytic layer fixes salt-tolerant phosphate solubilizing bacteria, potassium bacteria and exopolysaccharide-producing bacillus by using a charcoal-zeolite carrier, and the bacteria are distributed on the surfaces of the particles in a dotted manner. The fertilizer realizes organic combination of soil improvement, fertilizer supply and microbial regulation and control, can significantly reduce the soil salinity and alkalinity in a saline-alkali soil environment, and improves the fertilizer utilization rate and the crop growth performance.

The invention discloses a coagulant material, a preparation method and application, and the method comprises the following steps: adding a silane coupling agent into water for pre-hydrolysis to obtain a pre-hydrolysis solution; secondly, a mixed solution of aluminum chloride and ferric chloride is prepared and stirred to be completely dissolved and evenly mixed, and the mass ratio of aluminum chloride to ferric chloride is 9: 1-5: 5; the pre-hydrolysis solution and a mixed solution of aluminum chloride and ferric chloride are mixed and stirred evenly, and the ratio of the total substance mass of silicon to ferro-aluminum in the silane coupling agent is 0.1-0.5; dropwise adding a sodium hydroxide solution into the mixed solution, and adjusting the alkalization degree until the mass ratio of [OH] to [Al + Fe] is 1-2; and standing and curing the solution of which the alkalization degree is adjusted to obtain the aluminum-iron covalent composite coagulant. The coagulant has the advantages of efficient fluorine removal capability, rapid floc growth, good settling performance, low aluminum residue and the like, and is suitable for wide pH range and water quality conditions.

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a modified sodium ferric sulfate positive electrode material as well as a preparation method and application thereof. The chemical structural formula of the modified sodium ferric sulfate positive electrode material is Na < 2 + 2x > (Fe < 1-a-b > MaMb < 2-x > (SO4) z (PO4) < 3-z, a is more than 0 and less than 1, b is more than 0 and less than 3, z is more than 0 and less than 3, Ma and Mb are transition metal elements, and Ma is Ni; and Mb is Zn. The transition metal element is introduced and the doping proportion is controlled, so that fine regulation and control on the material performance can be realized, the conductivity and the ion diffusion rate of the positive electrode material are improved, and the structural stability and the air stability of the material are enhanced; the problems of slow Na < + > diffusion kinetics, poor crystallinity and poor material air stability of the sodium ferric sulfate positive electrode material are solved, and a new possibility is provided for the development of a sodium ion battery technology.

The invention relates to the technical field of electro-catalysis, in particular to a modified iron monatomic catalyst based on biomass carbon as well as a preparation method and application of the modified iron monatomic catalyst. The preparation method comprises the following steps: mixing and stirring chitosan, an acetic acid solution, thiourea and ferric chloride, adjusting the pH value to 7.5-8.5, and freeze-drying to obtain an aerogel precursor; pre-carbonizing the aerogel precursor to obtain a pre-carbonized product; mixing the pre-carbonized product with an alkali reagent, and calcining to obtain a metal nanoparticle doped monatomic catalyst; and carrying out ultrasonic treatment on the metal nanoparticle doped monatomic catalyst by using a mixed acid solution, washing to be neutral, and drying to obtain the modified iron monatomic catalyst. By adopting the modified iron monatomic catalyst provided by the invention, non-polar CO2 molecules and NO3 <-> are efficiently converted into urea under mild conditions, the yield of the urea is up to 2978.6 mu g h <-1 > mgcat <-1 >, and the maximum Faraday efficiency is up to 30.4%.

The preparation method comprises the following steps: (1) weighing a sodium source, an iron source, a phosphorus source and a carbon source, quickly and uniformly mixing, and then pre-sintering at low temperature to obtain a precursor; wherein the low-temperature presintering comprises two stages, in the first stage, the temperature is increased to 60-150 DEG C and kept for 1-3 h, and in the second stage, the temperature is increased to 200-350 DEG C and kept for 1-8 h; and (2) adding a carbon source into the precursor to prepare slurry, sanding the slurry, carrying out centrifugal spray drying, and carrying out high-temperature sintering to obtain the ferric sodium pyrophosphate positive electrode material. The precursor of the high-solid-content slurry can be prepared, the problem that the solid content of the slurry is low in the grinding stage of the sodium ferric pyrophosphate positive electrode material prepared by a solid-phase method is effectively solved, the solid content of the slurry is increased, the yield of the precursor is increased, the production cost is reduced, and meanwhile, the product quality is improved. The prepared ferric sodium pyrophosphate positive electrode material has relatively high compaction density, capacity and other performances, and the performance of the product is improved.

The invention provides a sodium vanadium fluorophosphate in-situ coated sodium ferric sulfate / carbon composite material and a preparation method thereof.The preparation method comprises the steps that raw materials including a reducing agent, an iron source, a sodium source and a carbon source are added into absolute ethyl alcohol to be stirred, sanded and mixed, and after obtained slurry is subjected to spray drying, the slurry is sintered and cooled in the argon atmosphere to obtain the sodium ferric sulfate / carbon composite material; mixing the sodium ferric sulfate / carbon composite material dispersion liquid with the sodium vanadium fluorophosphate precursor solution, performing hydrothermal reaction, centrifuging, washing and drying to obtain the sodium vanadium fluorophosphate in-situ coated sodium ferric sulfate / carbon composite material. According to the preparation method, a sodium vanadium fluorophosphate coating layer is generated on the surface of sodium ferric sulfate in situ by combining a low-temperature solid-phase method with a hydrothermal method, so that the sodium vanadium fluorophosphate in-situ coated sodium ferric sulfate / carbon composite material is obtained, the electronic conductivity of the composite material is greatly improved, and the sodium ion diffusion rate is promoted by coating of sodium vanadium fluorophosphate; fe2 + is prevented from being oxidized into Fe3 + due to direct contact between the sodium ferric sulfate and air, so that the air stability of the sodium ferric sulfate is improved.

The invention provides a method and system for recovering phosphate radicals, fluorine ions and sulfate radicals from phosphogypsum washing water step by step, and belongs to the technical field of industrial wastewater resourceful treatment. The method comprises the following steps: (1) adjusting the pH value of the wastewater to 3.0 + / -0.5, adding ferric sulfate according to the molar ratio of Fe to PO4 < 3-> of (1.0-1.5): 1, and selectively precipitating phosphate radicals to generate iron phosphate with the purity of more than or equal to 97%; (2) adjusting the pH value of the first filtrate to 4.7 + / -0.5, adding calcium fluoride seed crystals with the particle size of 50-200mm and CaCl2 (the molar ratio of Ca to F <-> is 0.5: 1-0.6: 1), and carrying out induced crystallization to recover calcium fluoride with the purity of more than or equal to 96%; and (3) adding Ca (OH) 2 (Ca: SO4 < 2-> molar ratio of 1.0: 1-1.2: 1) into the second filtrate, and directionally precipitating sulfate radicals to generate calcium sulfate dihydrate with the purity of more than or equal to 98%. According to the method, the pH and the precipitation sequence are controlled step by step, so that the problem of polyanion competition is solved, the recovery rates of phosphate radical, fluorine ion and sulfate radical respectively reach 98.8%, 96.3% and 97.5%, the content of PO4 < 3-> in purified water is less than or equal to 10 mg.L <-1 >, the content of F <-1 > is less than or equal to 5 mg.L <-1 >, and the content of SO4 < 2-> in purified water is less than or equal to 100 mg.L <-1 >, and the purified water can be directly recycled.

The invention belongs to the technical field of electrochemistry, and particularly provides a lanthanum-cerium double-doped sodium ferric sulfate positive electrode material and a preparation method thereof. The material is composed of a matrix and a carbon coating layer coating the matrix, the matrix has a chemical expression of Na6Fe4-x-yLaxCey (SO4) 7, x is greater than or equal to 0.01 and less than or equal to 0.1, and y is greater than or equal to 0.01 and less than or equal to 0.1. The material is prepared through spray drying and high-temperature sintering treatment in sequence, the particle morphology is regular, and the particle size distribution is uniform; the electronic conductivity and Na < + > diffusion rate of the material are remarkably improved by rare earth doping, so that the material has more excellent low-temperature cycle performance, sodium storage performance and the like.

The invention relates to the technical field of precious metal detection, in particular to a molybdenum detection reagent, a preparation method and a use method thereof, and the molybdenum detection reagent comprises 20%-38% of hydrochloric acid, 20%-27% of nitrate and water. The 316 stainless steel and the 2205 stainless steel both contain more than 2% of molybdenum, the 316 stainless steel and the 2205 stainless steel can be distinguished through magnetism, and the 2205 stainless steel has strong magnetism. The molybdenum detection reagent can be used for detecting molybdenum ions in stainless steel so as to distinguish 316 stainless steel from 304 stainless steel. The nitrate can make the 316 stainless steel and the 304 stainless steel show different colors, so that the 316 stainless steel and the 304 stainless steel can be accurately distinguished. The reagent of the magnesium nitrate can make the reagent on the 316 stainless steel yellow, the reagent of the aluminum nitrate can make the reagent on the 316 stainless steel light yellow, and the reagent of the ferric nitrate can make the reagent on the 316 stainless steel brown. The molybdenum detection reagent can accurately and rapidly detect and identify 316 stainless steel, and is low in cost, convenient to operate and convenient to carry.

The present invention discloses a method for separating nickel and iron from a nickel-iron alloy by chlorination roasting: (1) placing the nickel-iron alloy in a roasting furnace; (2) introducing a gaseous chlorinating agent into the roasting furnace for staged roasting to obtain roasting slag and a roasting gas phase; wherein the gaseous chlorinating agent is a mixture of chlorine and gaseous ferric chloride; and (3) condensing the roasting gas phase obtained in step (2) in stages to obtain solid ferric chloride and liquid silicon tetrachloride, respectively. The present invention controls the composition of the chlorinating agent during the chlorination roasting process to achieve selective and directional volatilization of iron into the gas phase while preventing nickel from being chlorinated. Thus, nickel and iron in the nickel-iron alloy can be separated in a single step, and the process flow is short.

The invention belongs to the technical field of sodium ion battery positive electrode materials, and discloses a preparation method and application of an iron ion doped sodium vanadium phosphate positive electrode material. Modification is carried out by doping iron ions in vanadium sites and taking citric acid as a carbon source for coating, iron nitrate nonahydrate serves as an iron source to participate in the modification process, meanwhile, citric acid is used for carrying out carbon coating on the material, and the citric acid and the doped iron ions synergistically increase the ionic conductivity, so that the problem that the sodium vanadium phosphate material is poor in conductivity is solved. Besides, in the sintering treatment process, the Na3V1.8 Fe0.2 (PO4) 3 / C positive electrode material obtained by doping 0.2 molar weight of iron ions and coating citric acid is always kept in the atmosphere of argon-hydrogen mixed gas, after circulation at the current density of 0.1 C to 20 C, the capacity recovery rate can reach up to 96.1%, and the capacity can still be kept to be 74.1% of the initial capacity at the high rate of 20 C; after 500 cycles under 1C current density, the capacity retention rate is 89.8%, while the capacity retention rate is only 72% after 500 cycles of pure NVP, the rate capability and cycling stability of the material are both improved, and the electrochemical performance of the material is effectively ensured.

The invention provides a method for reducing the content of magnesium, manganese and zinc impurity elements in iron phosphate, which comprises the following steps: (1) preparing a 1.2 mol / L ferrous sulfate solution, adding 25% ammonia water into the ferrous sulfate solution, adjusting the pH value, heating, stirring and reacting for 30 minutes, and filtering to obtain a purified ferrous sulfate solution; (2) preparing a 1 mol / L ammonium dihydrogen phosphate solution, and filtering to obtain a purified phosphorus salt solution; (3) dropwise adding 25% hydrogen peroxide into the purified ferrous sulfate solution to obtain a ferric sulfate solution; (4) dropwise adding a purified phosphorus salt solution into the oxidized ferric sulfate solution; (5) after the phosphorus salt solution is dropwise added, supplementing the purified ferrous sulfate solution according to the amount; (6) rapidly heating the solution and continuously reacting until the material turns white from yellow; and (7) washing the iron phosphate dihydrate precipitate until the conductivity is less than or equal to 200 us / cm, carrying out flash evaporation drying on the iron phosphate dihydrate filter cake, and calcining to obtain the battery-grade iron phosphate. The method can be widely applied to industrial production of iron phosphate.

The invention belongs to the field of ferrite materials, and particularly relates to a high-coercivity strontium ferrite with iron partially replaced by aluminum and a preparation method of the high-coercivity strontium ferrite. Aiming at the problem of low coercive force of a ferrite pre-sintering material in the prior art, iron is partially replaced by aluminum, ferric nitrate, strontium nitrate, aluminum nitrate and glucose are used as reaction raw materials, the ratio of the total molar weight of Fe and Al to the molar weight of Sr is (9.5-12): 1, the ratio of the molar weight of Al to the total molar weight of Fe and Al is (0-0.41): 1, and the molar weight of glucose is 0.5-3.5 times of the total molar weight of Fe, Al and Sr; and calcining at 900-1200 DEG C for 1-3 hours by adopting a solution self-combustion-aluminum ion substitution method to prepare the strontium permanent magnetic ferrite powder material with high coercivity.

The invention discloses a preparation method of a composite ferric sodium pyrophosphate material, which comprises the following steps: S1, uniformly dispersing a sodium source, an iron source, a phosphorus source, a carbon source and a surfactant in a solvent according to a stoichiometric ratio to form a dispersion liquid; s2, sanding the dispersion liquid at the temperature T1, discharging, and controlling the discharging temperature of the slurry to be T2; wherein the temperatures T1 and T2 meet the following conditions: 20 DEG C < = T1 < = 40 DEG C, 20 DEG C < = T2 < = 40 DEG C, and T1 > T2; and S3, carrying out spray drying on the slurry obtained in the step S2, and sintering to obtain the composite ferric sodium pyrophosphate material. According to the preparation method, the problem of slurry agglomeration can be improved to a great extent, so that the composite ferric sodium pyrophosphate material with high quality and good electrochemical performance is obtained.

The application provides an oilfield produced water treatment method. The method comprises the following steps: adding a polymeric aluminum ferric silicate solution into oilfield produced water to be treated, and stirring for a period of time at a first rotating speed; increasing the first rotating speed to a second rotating speed, adding a polyacrylamide solution, stirring for a period of time at the second rotating speed after the addition is completed, and then standing for a period of time; and filtering to obtain treated oilfield produced water. The method has the advantages of simplicity, high efficiency, low cost, easy operation, remarkable treatment effect and the like.

The invention discloses a ferromanganese phosphate precursor as well as a preparation method and application thereof, and relates to the technical field of battery materials. The method comprises the following steps: respectively preparing a manganous dihydrogen phosphate solution and a ferric sulfate solution; phosphoric acid, an oxidizing agent and a ferric sulfate solution are added into the manganese dihydrogen phosphate solution at the same time, or the manganese dihydrogen phosphate solution, phosphoric acid and the oxidizing agent are added into the ferric sulfate solution at the same time, the oxidizing agent is used for oxidizing manganese dihydrogen phosphate into manganese phosphate, ferric sulfate and phosphoric acid form ferric phosphate, and ferromanganese phosphate mixed slurry is obtained; aging the ferromanganese phosphate mixed slurry for crystal transformation, carrying out solid-liquid separation, and washing to obtain a ferromanganese phosphate filter cake; the ferromanganese phosphate filter cake is dried, calcined and smashed, a ferromanganese phosphate precursor is obtained, the chemical formula of the ferromanganese phosphate precursor is FexMn (1-x) PO4, and x ranges from 0.2 to 0.3. According to the method, a structure in which iron phosphate and manganese phosphate are mutually coated can be formed, and the hidden danger that the electrochemical performance of the lithium manganese iron phosphate positive electrode material is reduced due to non-uniform distribution of manganese and iron can be reduced.

The invention belongs to the field of medicines, and discloses a preparation process of ferric carboxymaltose, which comprises the following steps: oxidizing maltodextrin, performing ultrafiltration concentration, dissolving in a ferric trichloride aqueous solution, and performing coordination, ultrafiltration and spray drying to obtain powdery ferric carboxymaltose. The process has the advantages of simple amplification, no need of solvent application, low raw material cost and manufacturing cost, uniform product molecular weight distribution and the like, the dissolution rate of the obtained product is obviously higher than that of a product obtained by a precipitation process, and technical support is provided for more efficient preparation production.

The invention belongs to the technical field of soil improvement, and relates to a modified charcoal-polyaluminum ferric sulfate modifier and a preparation method thereof, and the preparation method specifically comprises the following steps: step 1, preparing charcoal; step 2, modifying the biochar; 3, preparing an aluminum-iron mixed solution; step 4, preparing polyaluminum ferric sulfate; step 5, preparing the modified charcoal composite polyaluminum ferric sulfate saline-alkali soil modifier; through multi-component compounding, nano modification, waste recycling and precise process control, the defects of single effect, high cost, poor timeliness, environmental risk and the like of the existing saline-alkali soil improver are comprehensively overcome. The core innovation point is that functional modification of biochar is combined with chemical characteristics of polyaluminum ferric sulfate, and a complex microbial inoculant is introduced to enhance biological activity, so that high efficiency, economical efficiency and environmental friendliness of saline-alkali soil improvement are realized.

The invention provides a method for increasing the iron-phosphorus ratio of an iron phosphate material. The method comprises the steps that S1, raw materials are prepared, wherein an ammonium phosphate solution, a phosphoric acid solution, a titanium dioxide ferrous solution and 30% hydrogen peroxide are prepared; s2, synthesis: adding an ammonium phosphate solution, a titanium dioxide ferrous solution and hydrogen peroxide into a reaction container, preserving heat, and performing suction filtration and washing until the conductivity of washing water is lower than 4000 [mu] S / cm to obtain a yellow primary washing filter cake; s3, conversion: weighing 5-15 kg of pure water, adding 200-400 g of ferrous sulfate and 200-600 g of a phosphoric acid solution, adding 2.5-3.5 kg of the yellow first-washing filter cake, and after pulpifying completely, heating, preserving heat, carrying out suction filtration and washing to obtain a pink second-washing filter cake; s4, calcining: drying, calcining and crushing to obtain a finished product iron phosphate; according to the method, ferrous sulfate is introduced as a catalyst in the process of converting ammonium ferric phosphate into ferric phosphate crystals, so that a material with a high iron-phosphorus ratio is obtained under the condition of low phosphoric acid dosage.

The utility model relates to the technical field of polyferric sulfate production, and discloses a high-purity polyferric sulfate drying device which comprises a drying box body and a stirring mechanism, the inner wall of the drying box body is sleeved with a driving shaft, the outer wall of the driving shaft is sleeved with a square placement frame, the outer wall of the square placement frame is fixedly connected with a pushing plate, and the pushing plate is fixedly connected with a stirring mechanism. A plurality of limiting sliding rods are arranged on the inner wall of the pushing plate and distributed on the inner wall of the pushing plate in a linear array shape. According to the high-purity polyferric sulfate drying device, the stirring mechanism is arranged in the drying box body, so that when the device works, a driving motor drives a driving shaft to drive a square placement frame to rotate, the device can stir ferric sulfate accumulated in the drying box body, and then the situation that the ferric sulfate is difficult to dry is reduced; and the drying efficiency of the heating lining on ferric sulfate accumulated in the drying box body is improved.

The invention discloses a simple high-throughput preparation method of spinel type nano high-entropy oxide, which comprises the following steps: 1) dissolving ferric nitrate, cobalt acetate, nickel acetate and at least two other different metal salts in a solvent to form a feed liquid A; 2) dissolving a precipitant in the same solvent as the solvent in the step 1) to form feed liquid B; 3) starting the supergravity reactor; 4) simultaneously introducing the feed liquid A and the feed liquid B into a supergravity reactor through a peristaltic pump to carry out a coprecipitation reaction, and obtaining a high-entropy oxide precursor solution after the reaction; 5) centrifuging and washing the high-entropy oxide precursor solution, and dispersing the high-entropy oxide precursor solution in water to obtain a clean precursor solution; 6) introducing the clean precursor solution into a hydrothermal kettle for hydrothermal reaction, and obtaining a nano high-entropy oxide solution after the reaction; and 7) carrying out alcohol washing on the nano high-entropy oxide solution, and drying to obtain the nano high-entropy oxide. The prepared oxide is high in quality, the particle size is 10-100 nm, and the oxide still has good dispersity under the condition that a modifier is not added.

The invention provides a porous ferric sodium pyrophosphate positive electrode precursor and a preparation method and application thereof, and the preparation method comprises the following steps: carrying out a co-precipitation reaction on a ferrous source solution, a phosphorus source solution, a pyrophosphate source solution, an oxidant solution, a precipitator solution and an organic polymer solution to obtain an intermediate material; and pre-calcining the intermediate material to obtain the porous ferric sodium pyrophosphate positive electrode precursor. According to the preparation method, a porous ferric sodium pyrophosphate positive electrode material precursor is prepared through in-situ coprecipitation and pre-calcination, in the coprecipitation process, an organic high-molecular compound is introduced in situ, after precipitation is completed, an intermediate product is calcined, the organic high-molecular compound is decomposed, and the porous ferric sodium pyrophosphate positive electrode material is obtained. The porous ferric sodium pyrophosphate positive electrode precursor with excellent charge-discharge capacity and cycle performance is obtained.

A composite positive electrode material precursor, a preparation method therefor, and the use thereof. The composite positive electrode material precursor comprises an N element-doped ferric phosphate core and an M element-doped ferric phosphate coating layer which coats the surface of the ferric phosphate core, the N element including at least one of Mn, Ni, Co, Cr, V, Mg, Sr, Nb, La, Nd, Ce and Y, and the M element including at least one of Al, Ti and Zr. The doping elements N and M are respectively introduced into the core and the coating layer of the positive electrode material precursor, so that the crystal structure of ferric phosphate can be regulated, thereby improving the conductivity and the ion diffusion rate thereof. Secondly, the doping elements N and M form a synergistic effect in the composite positive electrode material precursor, which optimizes the crystal nucleus structure, enhances the stability of the coating layer, regulates the electron structure and the like, thus comprehensively improving the structural stability, the cycle life, the ion transmission rate and electrochemical properties of positive electrode materials.

The present disclosure belongs to the technical field of lithium batteries, and particularly relates to ferric phosphate, a lithium ferric phosphate positive electrode material, preparation methods therefor, and the use thereof. The present disclosure uses a ferrous iron source and copperas together as iron sources, and controls the dosages of the two components to enable copperas to serve as not only an iron source but also a dopant, so that impurity elements, such as Ti, Mn and Mg, contained in copperas are introduced into ferric phosphate as beneficial doping elements and are further introduced into the lithium ferric phosphate positive electrode material. During a reaction process, a polymer monomer is polymerized in situ onto the surface of ferric phosphate, so as to limit the particle size of the material, thereby obtaining precursor particles having more uniform particle size and appearance. Thus, uniform coating and doping means can remarkably improve the electrochemical properties of lithium ferric phosphate. In addition, the preparation method for ferric phosphate provided by the present disclosure achieves high-added-value resource utilization on copperas without the need of impurity removal, thereby achieving the effects of reducing the cost and improving the efficiency.

The invention provides sodium ferric pyrophosphate and a preparation method thereof, and the preparation method comprises the following steps: mixing waste sodium ferric pyrophosphate with carbonate and an iron source to obtain a mixture, and calcining the mixture to obtain a calcined material; washing and filtering the calcined material to obtain a first filter residue and a first filtrate; performing impurity removal, concentration and crystallization on the first filtrate to obtain sodium carbonate; the first filter residues are subjected to acid pickling and filtering treatment, and second filtrate is obtained; adding phosphate and a pH regulator into the second filtrate, and heating for reaction to obtain mixed slurry; filtering the mixed slurry to obtain second filter residues, and sequentially drying, screening and deironing the second filter residues to obtain iron hydrogen phosphate; the preparation method comprises the following steps: mixing sodium carbonate with ferric hydrogen phosphate, then adding a doping agent, an auxiliary agent and a carbon source, and grinding and calcining to obtain the ferric sodium pyrophosphate. According to the method, high-purity sodium carbonate and iron hydrogen phosphate can be recycled, then pyrophosphate ferric sodium phosphate is prepared, and the pyrophosphate ferric sodium phosphate is good in particle dispersity, high in sphericity degree and high in capacity.